The WTB Nano Race 29er 2.1″ tire features an Aramid bead, DNA rubber, and a lightweight casing. The Aramid bead and lightweight casing definitely help drop weight, and at only 560 grams this tire is light and fast and definitely intended for use as an XC tire. According to WTB, the DNA rubber is a “fast-rolling 60a durometer rubber compound [...] specifically formulated for high-performance riding in a variety of conditions.” As for the Nano’s design itself, WTB claims:

“Its micro-knob design and large supportive casing conquer rough racecourses and roll with the punches on long trail rides. The elevated centerline tread rolls quickly on asphalt and hardpack, while the numerous working edges track predictably in ‘dust over crust’ conditions.”

Let’s see how accurate this description is, shall we?

Test
I’ve put close to 600 miles on the Nano as my rear tire on the Ibex Maroc. Over the course of my extensive test, I was very surprised to discover that despite being relatively narrow and so low-profile, the Nano provides excellent traction!
I think that the Nano’s traction in a variety of conditions can be attributed to the tacky DNA rubber. Despite having “micro” knobs, this tire seemed to stick to most stuff and provided plenty of power as I climbed up and ripped down the mountain, whether I was in Colorado or Georgia.
I’ve found that the description WTB gives above is pretty much spot-on. This tire is great in hardpack and “dust-over-crust” conditions, and I would add that it also handles well in rocky conditions (as long as the rocks are dry).

Negatives
As you might expect, this small-knobbed tire came up short in a few areas. Anytime the conditions were somewhat wet, the Nano started having difficulties. And it particularly hates wet roots. Trying to climb up a damp, root-infested slope that’s a little off-camber? Forget about it.
As I mentioned above, the Nano features a super-tacky rubber compound. While tacky rubber equals good traction, it doesn’t equal longevity. At about 400 miles, the Nano was already showing significant wear, and looked ready to be replaced. After 600 miles, I am in dire need of a new tire.

Before / After 400 miles.

After 600 miles.

Final Verdict
Due to the low weight and the extremely low-profile knobs, the Nano is a fast rolling tire! As the “race” designation obviously indicates, this tire is meant to be raced. It’s not really designed to be an everyday, do-it-all tire for the average Joe but if you’re looking for speed on a dry course, be sure to give the Nano a try!MSRP on the Nano Race is $65 per tire.